Improvement in electro-magnetic alarms



WILLIAM B. e u E-RNSEY.

Improvement in Electro-Magnetic Alarms.

Patented April 30, 1872.

UNITED STATES PATENT QFFIGE.

IMPROVEMENT IN ELECTRO-MAGNETIC ALARMS.

Specification forming part of Letters Patent No. 126,287, dated April30, 1872.

Specification of an Improvement in Electro- -Magnetic Alarms, inventedby WILLIAM B.

GUERNSEY, of Jersey City, in the county of Hudson, State of New Jersey.

This invention consists, first, in controlling the circuit of anelectromagnetic alarm by two or more mechanical circuit-breakers in sucha way that electric pulsations or intermittent impulses will be causedand any variation in the proper pulsations or any interference therewithwill cause an alarm by disturbing the synchronism of thecircuit-breakers. The invention consists, second, in'combining with eachother and with other elements of an electromagnetic alarm two or morecircuits controlled by circuit-breaking devices in such a manner thatthey will act synchronously and will cause an alarm in the event oftheir correspondence or synchronous action being interfered with, or inevent of the circuit which they control, or either of them, beingrelieved from or made independent of their actions. The inventionconsists, third, in connecting two such synchronous circuits separatelywith the respective helices of one magnet or its equivalent, so that thesaid magnet may be excited, to cause an alarm on the occurrence of anyinterruption of the synchronous action of the circuits. The inventionconsists, fourth, in combining with two or more synchronous circuits,arranged to operate as setforth, apermutation mechanism by which theintervals or duration of the impulses may be varied, as a furthersafeguard against pick- 1ng.

It will be manifest that various devices may be used in connection withtrains of gearing to efiect the synchronal opening and closing of thecircuits.

One mode of carrying my invention into effect is illustrated in theaccompanying draw ing, in which- Figure 1 is a diagram of an apparatus,including a permutation arrangement, which illustrates what is referredto above as the fourth part of the invention. Fig. 2 is a section at y 3Fig. 1. Fig. 3 is a sectional elevation of the apparatus hererepresented consists, in its simple form, of two circuits, in each ofwhich is introduced a circuit-breaker formed of a wheel or cylinder, Aor A of non-conducting material, in the periphery of which are inserted,parallel with the axis, metallic strips, serving, as the wheel rotates,to form, at intervals, electrical connection between the ends of a pairof springs, 11. a or b N, which press upon the periphery of the rotatingcylinder. The two wheels or cylinders being connected so as to move inunison, the two circuits will be broken simultaneously and reclosedsimultaneously. The two contact breakers or makers A and A are mountedupon shafts S and S These shafts are supposed to be rotated each byclock-work regulated to run as nearly at like speeds as may be.Supposing the wires 00 x to be connected as indicated by the dotted line00 or by other means, and the wires g 3 also connected, it is evidentthat when either pair of the springs a at or b I) rest or impinge uponone of the pieces of metal in the faces of said wheels such pair will beelectrically connected, and that if said wheels revolve at precisely thesame speed and are provided with contact strips corresponding in number,position, and width, two simultanneous circuits will be established,proceeding from battery B as many times during the rotation of saidwheels as there are metallic strips or surfaces upon their faces and ifeach of these circuits be of same length or resistance, the effect ofeach upon magnet M will be the same. It is, therefore, only necessary toconduct the said circuits, each through its respective helix, of magnetM in a contrary direction, to insure that they will entirely neutralizeeach other, producing no effect upon the magnet; but if either of saidcircuits be broken or interrupted, or if a cross-circuit be established,as, say, between w 00 then M would be likely to be afl'ected by one orthe other circuit solely, and so would become a magnet and attract itsarmature g, thereby setting in motion some devices, causing an alarm.

I do not desire to limit myself to any specific mechanism for soundingan alarm, but have represented in Fig. 3 an eflicient device for thispurpose. Some features of this device I have made the subject of aseparate application for Letters Patent. It is adapted to sound acontinuous alarm, which, when once started by any disturbance in eitherof the main circuits, cannot be stopped by any subsequent act at thepoint where the disturbance originated. The drawing down of the armature9 establishes a new local circuit, which, by means of the vibrator E,contact-stop e, and branch wires V V, is caused to pass alternatelythrough the bell-magnet U and around the same, so as to vibrate thehammer T in the usual manner. A mechanical alarm can be employed, ifpreferred.

One of the contact-breakers, with its clockwork and belongings, is to belocated at the point to be protected, and the other, with battery-magnetand bell at some other place, as, say, a police-station or the residenceof owner, and it is to protect the conductors w x {D2 connectin g thetwo that this invention is designed.

The synchronism of the two movements may be insured by use of thetoothed wheels a b, magnets 01 h, and arrangement of springs andcircuits shown. The speed of shafts S and S (driven by clock movements)being known and the limit of probable error of the driving-clocksascertained, such number of teeth are put into a b as will insure one ofthem passing a certain point in the revolution often enough to keep theerror in the going of the clocks less than the time required to saturatethe magnet M and affect its armature. It is necessary, also, that at thepoints on the peripheries of the wheels A A corresponding to said teeththere shall be a space of non-conducting material of sufiicient width tomake it certain that there shall be at that time no contact through thesprings. The magnets h d are arranged as shown, so that their armatures,when open, will arrest the wheels b a as the successive teeth arriveover them. Then, if one of the teeth, in say b, is arrested by thearmature of h, it will be there held until the corresponding tooth of (1comes in contact with armature of d, or vice versa, at which moment acircuit will be closed through as, 0, S b, h, 00'', W, s, a, and d, toB, saturating both magnets d and h, causing them to attract theirarmatures and release d and a, thus taking up or condoning all the pasterror, and startin g both movements exactly together for another stage,or until the arrival of the next tooth. It is also necessary to thecorrect working of this device that the contact-breakers n be widerthanthe probable error.

In order to insure the sounding of the alarm in the event of the exposedcircuit-wire being severed at the instant while the springs b b may beinsulated and the shaft S arrested by its check-wheel a, I apply to theshaft S two pulleys, O and P, both insulated from the shaft but rotatedthereby. The pulley O is fast upon the shaft, but the pulley P has alimited motion thereon if the rotation of the shaft be suddenlyarrested. This motion throws pins 0 p upon the faces of the pulleys intoelectrical contact, causing a current from 3 through 0 and p, to thealarm-magnet. This effect will not be produced by the checking of thewheel a for an instant to await the arrival of b, but

will be caused by the permanent stoppage of the shaft. Other expedientsmay be devised for this purpose. A spring, 19 restores the pulley P toits original position.

Another and abetter method of obtaining synchronism allows me todispense with wheels 0 and P and their belongings, as also with thecontact-breakers n on wheel G. I have only to arrange wheels A and F andA and F so that the two circuits shown shall be completed upon eachapproach of a tooth in wheels a and b to the respective stops onarmatures of magnets d and h, and to make the resistance of each helix Rof magnet M considerably greater than that of the circuits through therespective magnets h and d, to insure the same results as are obtainedby method shown. And these devices can be varied almost infinitely.

In the foregoing description no allusion has been made to thepermutation mechanism represented in the lower part of Fig. 1. This isnot essential to the effective working of the principal part of myinvention, but may be arranged to vary the intervals or duration of thesuccessive synchronous pulsations to such a degree as to preclude thepossibility of imitating the effect, for the purpose of tampering withthe apparatus, without detection.

F F are contact breakers and makers, consisting of non-couductin gwheels with metallic strips similar to the wheels AA, but with thewidths or distances of the contact surfaces varied, if required. a a andI) b are pairs of springs pressing upon the peripheries of the wheelsand connected to the wires 3 3 m a respectively, as shown, theconnections m being omitted. The wheels F F are keyed upon shafts f f,driven by means of clock-work or by gearing f connecting them with theshafts S and 8, respectively, so that the least common multiple ofrotation of the two shafts S f or 8 f would occupy a long period. It,now, the contact-surfaces on the two wheels A F or A F be numerous andirregular, and never alike on any two machines, it is evident that aprinciple of permutation is introduced into the arrangement which can bemade to run through so many hours as to render it practicallyimpossible, from that cause alone, for an evil-disposed person toascertain what electrical impulses were likely to pass over the circuita: m a, in any given time. With such knowledge it would be scarcelypossible that the arrangement could be picked; without it it is certainthat it could not be.

Fig. 4 illustrates a modified form of permutation mechanism, and Iintend, by showing these two forms, to indicate that the arrangements orappliances for this purpose admit of numerous variations withoutlimiting myself to either form.

A represents a contact maker and breaker, consisting of a wheel ofnon-conducting material, made in two parts or with divided or separatecontact-strips arranged irregularly on the respective parts. On theperiphery of this divided wheel press springs 1 2 3, the middle one 2resting on both parts of the wheel so as to form a connection with everysuccessive contactsurface on either part. The spring 1 touches thecontact-surfaces on one part of the wheel and the spring 3 those on theother part. It will, hence, appear that as each contactstrip of one partof the wheel reaches the springs it forms an electrical connectionbetween 1 and 2, and that each strip on the other part forms aconnection between 2 and 3; but these respective connections are notmade simultaneously, but in an irregular manner. F is a wheel, also madein two parts, and driven by clock-work or by gearing from the wheel A insuch a manner that A may perform a number of revolutions for onerevolution of F The wheel F is provided with divided contact-strips ofvaryingwidths. These strips are not arranged irregularly as those on thewheel A but are set in alternate positions around the wheel, so that acontact-surface on one part will be opposite an insulating surface onthe other part, or vice versa, around the entire periphery. Threesprings, 4 5 6, bear on the periphery of the wheel F the center one 5receiving contact from every metallic strip, so that the said spring 5will be placed in electrical connection with 4 and 6 alternately. Thewire as is attached to the spring 2; m unites 3 and 4; m is attached to5; and a supplemental wire, at, unites the supplemental springs l and 6.The office of the wheel F is to place 00 into connection with m and acalternately. The effect of this arrangement is v such that the sequenceof breaks and contacts a second electrical circuit may be made themeansof detecting any variation in the normal pulsations of an exposedelectrical circuit whether such variation be produced by cutting,short-circuiting, or other tampering with the conductors, or by thedoing of any act which the apparatus is arranged to detect. Thisgeneralresultmay be accomplished by other means of combining two or moresynchronous mechanical circuit-breakers, a plurality of circuits notbeing essential.

Having thus described my invention, I wish it distinctly understood thatI do not desire to limit myself to the details or mechanism hereinspecified; but

What I claim as new, and desire to secure by Letters Patent, is-

1. An electrical circuit, an alarm mechanism, and two or moresynchronous mechanical circuit-breakers or changers, or two or moreautomatic circuit-breakers, the combined action of which are synchronouswith another or others so combined that any interruptions or variationof the normal pulsations in the conductor will cause an alarm.

2. An electromagnetic circuit and amechanical device for causing thecurrent to pass through it in pulsations, irregular in interval,duration, or intensity, in combination with an alarm which will becaused to sound in the event of the normal succession of pulsationsbeing interfered with.

3. A single electromagnetic circuit controlled by one or more mechanicalcircuit-breakers or changers, in combination with an alarm when arrangedso that an alarm will be had if the said circuit be broken orshort-circuited, or if the normal sequence of electrical impulses beinterfered with.

4. An electromagnetic circuit in combination with two or more mechanicalcircuit'breakers and other appliances for causing two sets of impulsesin the same conductor, one of which will and the other will not affectthe movements of the circuit-breakers, or one controlled by and theother controlling the movements of the circuit-breakers.

5. The combination, with one or more electromagnetic circuits, of two ormore mechanical circuit-breakers or changers which act independently onthe circuit or circuits, but are themselves controlled synchronously byelectricity.

6. The combination of two or more electromagnetic circnits controlled bysynchronous mechanical circuit-breakers and an alarm so arranged thatthe alarm will be actuated by any interruption of the synchronouspulsations of the circuits.

7 The two electromagnetic circuits connected separately to therespective helices of a magnet, and caused to act in unison oropposition by the agency of synchronous mechanical circuit-breakers.

8. Secondary circuit-breakers or permutation appliances when combinedwith an electromagnetic circuit, an alarm and mechanical devices torender the action of the circuit-breakers synchronous, substantially asset forth.

W. B. GUERNSEY.

Witnesses:

OOTAVIUS KNIGHT, WALTER ALLEN.

